Update multiple object attributes at once

I have such a data model with topic and entry:

class Topic(models.Model):
    """A topic the user is learning about."""
    text = models.CharField(max_length=200)
    date_added = models.DateTimeField(auto_now_add=True)
    owner = models.ForeignKey(User)

    def __str__(self):
        """Return a string representation of the model."""
        return self.text

class Entry(models.Model):
    """Something specific learned about a topic"""
    topic = models.ForeignKey(Topic)
    title = models.CharField(max_length=200)
    text = models.TextField()
    tags = models.CharField(max_length=200)
    date_added = models.DateTimeField(auto_now_add=True)

    class Meta:
        verbose_name_plural = 'entries'

    def __str__(self):
        """Return string representation of the model"""
        return self.text[:50] + "..."

I intend to retrieve the entries whose topic is questions and title starts with numerals,
then change the unqualified titles to
the qualified title which I set is the first line retrieved from entry's text.

entries = (Entry.objects
                .filter(topic__text="Questions")
                .filter(title__regex=r"^\d+"))

In[63]: [entry.title for entry in entries]
Out[63]: ['1', '1', '1', '1', '1']

Replace the integer with the first line of entry's text as the title:

def first_line(text): return re.search(r".+", text).group()

for entry in entries:
    new_title = first_line(entry.text)
    setattr(entry, 'title', new_title)
    entry.save()

I am novice of Django, and wondering:

1. If "regex" is a best solution to filter titles startswith a numerical?
2. entry.save() is implemented multiple times, could all the changes be saved in one go?
3. Could such operations be handle on database level?